Today there is a great need to measure the degree of alignment of two axle couplings on-line, i.e., during operation. By having the axles oriented in a collinear direction (in line with the directions of symmetry of the axles), one achieves fewer energy losses when the electrical machine is driving a pump via axle and axle coupling, and also the wear on the axles, couplings, and electrical machines is minimized. The measurement and subsequent orienting is done today with laser-based systems when the axles are stationary. However, it is known that the collinearity of the axles during operation, on account of the loading and temperature changes, differs from the condition when they are standing still. Likewise, the orientation changes over time during operation. Therefore, there is great interest in a number of different branches of industry in on-line measurement of axles and axle couplings in order to make possible an orientation which coincides with the conditions during operation.
The environmental aspects in the industry with temperatures in axle couplings of up to 150° C. and the dirty environment dictate the use of a sensor system which can handle these requirements. Magnetic sensors are popular today, for example in the automotive industry, where one can find such an environment.
GB 2360596 and GB 2321969 deal with axle orientation layouts.